Add the "Obtaining The Code" subsection in the top-level README.md file.

No changes to code.

README.md

@@ -8,6 +8,48 @@ If you are reading this on a Git mirror someplace, you are doing it wrong.
 The [official repository](https://www.sqlite.org/src/) is better.  Go there
 now.
 
+## Obtaining The Code
+
+SQLite sources are managed using the
+[Fossil](https://www.fossil-scm.org/), a distributed version control system
+that was specifically designed to support SQLite development.
+If you do not want to use Fossil, you can download tarballs or ZIP
+archives as follows:
+
+  *  Lastest trunk check-in:
+     <https://www.sqlite.org/src/tarball/sqlite.tar.gz> or
+     <https://www.sqlite.org/src/zip/sqlite.zip>.
+
+  *  Latest release:
+     <https://www.sqlite.org/src/tarball/sqlite.tar.gz?r=release> or
+     <https://www.sqlite.org/src/zip/sqlite.zip?r=release>.
+
+  *  For other check-ins, substitute an appropriate branch name or
+     tag or hash prefix for "release" in the URLs of the previous
+     bullet.  Or browse the [timeline](https://www.sqlite.org/src/timeline)
+     to locate the check-in desired, click on its information page link,
+     then click on the "Tarball" or "ZIP Archive" links on the information
+     page.
+
+If you do want to use Fossil to check out the source tree, 
+first install Fossil version 2.0 or later.
+(Source tarballs and precompiled binaries available
+[here](https://www.fossil-scm.org/fossil/uv/download.html).)
+Then run commands like this:
+
+        mkdir ~/sqlite
+        cd ~/sqlite
+        fossil clone https://www.sqlite.org/src sqlite.fossil
+        fossil open sqlite.fossil
+
+After setting up a repository using the steps above, you can always
+update to the lastest version using:
+
+        fossil update trunk   ;# latest trunk check-in
+        fossil update release ;# latest official release
+
+Or type "fossil ui" to get a web-based user interface.
+
 ## Compiling
 
 First create a directory in which to place
@@ -18,13 +60,13 @@ script found at the root of the source tree.  Then run "make".
 
 For example:
 
-    tar xzf sqlite.tar.gz    ;#  Unpack the source tree into "sqlite"
-    mkdir bld                ;#  Build will occur in a sibling directory
-    cd bld                   ;#  Change to the build directory
-    ../sqlite/configure      ;#  Run the configure script
-    make                     ;#  Run the makefile.
-    make sqlite3.c           ;#  Build the "amalgamation" source file
-    make test                ;#  Run some tests (requires Tcl)
+        tar xzf sqlite.tar.gz    ;#  Unpack the source tree into "sqlite"
+        mkdir bld                ;#  Build will occur in a sibling directory
+        cd bld                   ;#  Change to the build directory
+        ../sqlite/configure      ;#  Run the configure script
+        make                     ;#  Run the makefile.
+        make sqlite3.c           ;#  Build the "amalgamation" source file
+        make test                ;#  Run some tests (requires Tcl)
 
 See the makefile for additional targets.
 
@@ -43,13 +85,13 @@ with the provided "Makefile.msc" to build one of the supported targets.
 
 For example:
 
-    mkdir bld
-    cd bld
-    nmake /f Makefile.msc TOP=..\sqlite
-    nmake /f Makefile.msc sqlite3.c TOP=..\sqlite
-    nmake /f Makefile.msc sqlite3.dll TOP=..\sqlite
-    nmake /f Makefile.msc sqlite3.exe TOP=..\sqlite
-    nmake /f Makefile.msc test TOP=..\sqlite
+        mkdir bld
+        cd bld
+        nmake /f Makefile.msc TOP=..\sqlite
+        nmake /f Makefile.msc sqlite3.c TOP=..\sqlite
+        nmake /f Makefile.msc sqlite3.dll TOP=..\sqlite
+        nmake /f Makefile.msc sqlite3.exe TOP=..\sqlite
+        nmake /f Makefile.msc test TOP=..\sqlite
 
 There are several build options that can be set via the NMAKE command
 line.  For example, to build for WinRT, simply add "FOR_WINRT=1" argument